    true
    ""))
 
-(def ppa-tokens-to-surface
+(defonce ppa-tokens-to-surface
   (map (fn [pair]
          [(re-pattern
            (str "\\b" (first pair) "\\b"))
           (second pair)])
        preposition-plus-article))
 
-(def ppa-surface-to-tokens
+(defonce ppa-surface-to-tokens
   (map (fn [pair]
          [(re-pattern
            (str "\\b" (second pair) "\\b"))

   [dag_unify.core :refer (copy dissoc-paths fail? get-in ref? strip-refs unify)]))

;; TODO: convert all morphology rules to this format used for prepositions:
(def preposition-plus-article
  [["a il"   "al"]
   ["a lo"   "allo"]
   ["a la"   "alla"]

                lexeme))
        (get lexicon surface-form))))

(defonce exceptions-rules
  (concat verbs/exceptions-rules
          adjectives/exceptions-rules
          nouns/exceptions-rules))
